Nested ContourLayout causing StackOverflow

The following code causes a stack overflow during layout:

    class ParentView(context: Context): ContourLayout(context) {
        init {
            setBackgroundColor(Color.RED)
        }

        val childView = ChildView(context).apply {
            applyLayout(
                x = leftTo { parent.left() }.widthOf { 100.xdip },
                y = topTo { parent.top() }.heightOf { 100.ydip }
            )
        }
    }

    class ChildView(context: Context) : ContourLayout(context) {
        init {
            setBackgroundColor(Color.BLUE)
        }
    }

However, moving ChildView’s applyLayout into it’s onInitializeLayout solves the issue:

    class ParentView(context: Context): ContourLayout(context) {
        init {
            setBackgroundColor(Color.RED)
        }

        val childView = ChildView(context).also { addView(it) }
    }

    class ChildView(context: Context) : ContourLayout(context) {
        init {
            setBackgroundColor(Color.BLUE)
        }

        override fun onInitializeLayout() {
            super.onInitializeLayout()
            applyLayout(
                x = leftTo { parent.left() }.widthOf { 100.xdip },
                y = topTo { parent.top() }.heightOf { 100.ydip }
            )
        }
    }

I don’t know if this is a bug or not, but my hunch is it’s the intended behavior (if not, I’d be happy to look into it).

I realize nesting layouts is discouraged, but there are going to be situations where it is useful and people are going to do it anyway.

The pattern Contour uses for configuring child views (MyView(context).apply { applyLayout() }) is great, and it seems clunky to have to violate it iff the child happens to be another ContourLayout (I can imagine during refactoring a View that didn’t start as Contour might become one later).

Could we make it so layout constraints declared at construction time get deferred until onInitializeLayout? Either by having applyLayout behave differently for ContourLayouts or with an onInitializeLayout DSL:

    class ParentView(context: Context): ContourLayout(context) {
        init {
            setBackgroundColor(Color.RED)
        }

        val childView = ChildView(context).apply {
            onInitializeLayout {
                applyLayout(
                    x = leftTo { parent.left() }.widthOf { 100.xdip },
                    y = topTo { parent.top() }.heightOf { 100.ydip }
                )
            }
        }
    }

    class ChildView(context: Context) : ContourLayout(context) {
        init {
            setBackgroundColor(Color.BLUE)
        }
    }

[saket]

I share your pain. We have a work-in-progress solution for this.

[dimsuz]

Getting caught by this over and over. (I keep forgetting about this issue). I use ContourLayout extensively in my new project, so naturally often child views are also CountourLayouts. Having to use .let instead of .apply makes code look irregular.

If possible I’d suggest to increase priority of this bug.